CN205063929U - Colliery is sealed in pit and is pressed integration segmentation hydraulic fracturing device - Google Patents

Abstract

The utility model discloses an integrated segmental hydraulic fracturing device for coal mine sealing and pressure, which comprises an orifice anchor, a first sealing capsule, a one-way valve, a second sealing capsule, etc. arranged sequentially on a coiled tubing; The tubing passes through the middle of the first and second packing capsules and there are water outlet holes inside the capsules. The coiled tubing is externally connected to the fracturing pump, and a plug is installed at the end. The first and second packing capsules and the coiled tubing pass through a high-pressure hose collar It is fixedly connected with the anti-protrusion washer, and the one-way valve is connected with the coiled tubing with threads. Compared with the traditional downhole drilling method of sealing first and then pressing and only performing hydraulic fracturing for one full drilling, the utility model realizes the integration of isolation and fracturing, and can isolate the drilling into multiple sections, segmented Carry out hydraulic fracturing to open more uniform gaps in the coal seam, with simple structure and strong operability.

Description

An integrated segmental hydraulic fracturing device for coal mine underground pressure sealing

technical field

The utility model relates to the technical field of an integrated segmental hydraulic fracturing device for sealing and pressure underground in coal mines.

Background technique

A large amount of gas produced during coal mining poses a major threat to the safe production of coal mines. For a long time, coal production technicians have been working hard to reduce gas gushing in the process of coal mining. Pre-extraction of coal seam gas before mining is an important means to control the gas problem in my country. However, the air permeability coefficient of coal seams in my country is generally low, and it is difficult to achieve the ideal drainage effect by general pre-mining pre-drainage.

At present, hydraulic fracturing of coal seams before gas drainage, as an effective coal seam permeability enhancement technology, has gradually been applied on a large scale in many places. However, in the current hydraulic fracturing, the borehole is generally only subjected to one full borehole fracturing, and the corresponding hole sealing method is to run the fracturing string into the borehole, and use a packer or cement mortar or Polyurethane chemical slurry annulus seals the orifice, and high-pressure water can easily open a large number of fractures in the weak coal seam in the borehole, and even communicate with other adjacent boreholes along a main fracture to increase the permeability of other places that are not easy to fracture It is not ideal, which makes the gas permeability coefficient of the coal seam at the local position of the drill hole not greatly improved, and reduces the fracturing efficiency of a single hole. Excessive gas gushes out, and the unevenness of this anti-permeability effect seriously restricts the application and popularization of hydraulic fracturing technology. In addition, the method of drilling all holes in one fracturing requires the fracturing equipment to provide a large fracturing displacement and high injection pressure, so this makes the downhole fracturing equipment bulky and complex, and is not suitable for underground roadways Narrow and limited working space.

Therefore, inventing a fracturing and sealing method that can shorten the length of the fracturing section, make the cracks opened in the coal seam more uniform, improve the fracturing efficiency, and better adapt to the operating characteristics of the downhole has become a key to promote the application and promotion of hydraulic fracturing technology. The essential.

Contents of the invention

The purpose of the utility model is to overcome the deficiencies in the above-mentioned technologies and provide a hydraulic fracturing device with simple structure and convenient operation.

The technical scheme adopted by the utility model is: an integrated segmental hydraulic fracturing device for coal mine sealing and pressure, which includes an orifice anchor, a first sealing capsule, a one-way valve, and a second sealing capsule.

The coiled tubing passes through the middle of the first and second packing capsules and has a water outlet hole inside the capsules.

The external end of the coiled tubing is connected with a hydraulic fracturing pump, and the end is provided with a plug.

The sealing capsule and the coiled tubing are fixedly connected through a high-pressure pipe collar and an anti-burst gasket.

The one-way valve is provided with two symmetrically distributed liquid injection holes, and the one-way valve is connected with the coiled tubing with threads.

The starting pressure of the one-way valve is 5MPa.

Compared with the traditional hydraulic fracturing method of single-hole one-time full-hole drilling, the utility model adopts the method of connecting two sealing capsules in series to separate the entire drilling into multiple sections, and concentrates the pressure on a small section for fracturing each time, and then presses Hydraulic fracturing is carried out section by section in a certain order. Since the action surface is more concentrated, the cracks opened in the coal seam are more uniform, which greatly improves the fracturing efficiency and reduces the water flow, thereby reducing the requirements for the fracturing system. The volume of the equipment is greatly reduced, which can better adapt to the underground roadway conditions, has strong operability, and is convenient for technology promotion.

Description of drawings

Fig. 1 is a schematic diagram of the structure before fracturing in the present invention.

Fig. 2 is a schematic diagram of the structure after fracturing in the present invention.

In the figure, 1—coiled tubing, 2—the first packing capsule, 3—one-way valve, 4—the second packing capsule, 5—water outlet hole, 6—high pressure pipe collar, 7—screw thread, 8—liquid injection Hole, 9—fracturing pump, 10—orifice anchor, 11—plug, 12—drilling.

detailed description

As shown in Figure 1, an integrated segmental hydraulic fracturing device for coal mine underground pressure sealing, including an orifice anchor (10), a first packing capsule (2), a one-way Valve (3), second packing capsule (4).

In particular, the coiled tubing (1) passes through the middle of the first and second sealed capsules and has a water outlet hole (5) inside the capsules.

In particular, a hydraulic fracturing pump (9) is connected to the outer end of the coiled tubing (1), and a plug (11) is arranged at the end.

In particular, the packing capsule is fixedly connected to the coiled tubing (1) through a high-pressure pipe collar (6) and an anti-burst gasket.

In particular, the one-way valve (3) is provided with two symmetrically distributed liquid injection holes (8), and the one-way valve (3) is connected with the threaded thread (7) between the coiled tubing (1).

In particular, the starting pressure of the one-way valve (3) is 5MPa.

As shown in Figure 2, the present invention is used in cooperation with other downhole fracturing equipment. First, run the fracturing string into the predetermined position in the borehole (12), turn on the fracturing pump (9), and high-pressure water enters the first packing capsule (2) through the water outlet hole (5) on the coiled tubing (1) and the second sealing capsule (4), the high-pressure water makes the sealing capsule expand and set, and is in close contact with the borehole wall, forming a closed space between the two sealing capsules. As the pressure rises, after the high-pressure water pressure in the coiled tubing (1) reaches the starting pressure of the check valve (3) 5MPa, the check valve (3) opens, and the high-pressure water passes through the injector of the check valve (3). The liquid hole (8) enters into the closed space formed by the packing capsule, and as the injection pressure increases continuously, the high-pressure water fractures the coal seam, opens and expands new fractures in the coal seam, and communicates and extends secondary fractures. After the fracturing is completed, the fracturing pump (9) is turned off, the sealing capsule is unsealed, and the fracturing string is lifted out of a fracturing unit, and the above steps are repeated until the fracturing work of the entire borehole (12) is completed.

Claims (6)

1. the integrated segmentation fracturing device of underground coal mine envelope pressure, is characterized in that: comprise opening anchor, the first packing capsule, one way valve, the second packing capsule, plug that coiled tubing sets gradually.

2. the integrated segmentation fracturing device of a kind of underground coal mine envelope pressure according to claim 1, is characterized in that: described coiled tubing passes first, second packing capsule centre and divides in capsule and has weep hole.

3. the integrated segmentation fracturing device of a kind of underground coal mine envelope pressure according to claim 1, is characterized in that: described coiled tubing outer end is connected to fracturing pump, and end is provided with plug.

4. the integrated segmentation fracturing device of a kind of underground coal mine envelope pressure according to claim 1 and 2, is characterized in that: described packing capsule is fixedly connected with by high pressure pipe collar and protrusion-dispelling packing ring with coiled tubing.

5. the integrated segmentation fracturing device of a kind of underground coal mine envelope pressure according to claim 1, is characterized in that: described one way valve is provided with two symmetrical liquid injection holes, screwed connection between one way valve and coiled tubing.

6. the integrated segmentation fracturing device of a kind of underground coal mine envelope pressure according to claim 1, is characterized in that: described one way valve starting pressure is 5MPa.